Dual-sided solar panels could improve energy in homes

Dual-sided solar panels have the potential to produce 20% more energy than traditional one-sided systems if used properly on residential rooftops, according to research from the Australian National University (ANU).

Dual-sided or bifacial solar cells allow for both the front and back of the solar panel to generate power. The back of the panel collects energy reflected from the roof. Bifacial panels are used in commercial solar power systems but remain underutilised in the residential solar market, where monofacial modules are more commonly used.

Monofacial modules generally have a white or black backsheet compared to their bifacial counterpart, which is made with glass on both sides.

Dr Marco Ernst from ANU, lead author of the study, said the findings show the benefits of dual-sided systems, while addressing a gap in understanding the viability of bifacial technology on rooftops.

“We conducted detailed optical and electrical modelling to assess the potential energy gains of bifacial rooftop PV systems compared to monofacial arrays.

“Bifacial solar modules on flat rooftops have demonstrated the potential to generate up to 22.6% more energy compared to monofacial solar modules,” Ernst said.

Rooftop colour is a key factor in increasing a bifacial solar power system’s performance, and system and module design should also be carefully considered. Lighter colours typically have higher solar reflectivity.

This is a critical factor in maximising the potential of bifacial solar panels, emphasising the importance of considering the specific characteristics of rooftop surfaces, according to Ernst.

“For example, light-coloured roofing is crucial for creating optimal reflectivity and is in line with NetZeroCities approaches.”

As record heatwaves sweep the globe, cities are tackling the problem with innovative solutions, such as painting white roofs to lower soaring heat.

In 2021, the New South Wales Government introduced a dark roof ban for new homes to reduce heat and energy costs, but this was scrapped a year later as the policy was unpopular with property developers.

According to Ernst, cool materials such as light-coloured roofing can radiate heat rather than absorb it, and the mainstream adoption of this would reduce heat in urban areas, as well as energy consumption and costs, helping Australia reach net zero by 2050.

The International Technology Roadmap for Photovoltaic (ITRPV) estimates that the world share of bifacial modules by 2033 will be 70%.

“It would be in Australia’s best interest to act quickly and incentivise the use of light roofs to fight climate change and to futureproof the industry for what’s coming,” Ernst said.

The research has been published in Energy Conversion and Management.

Image credit: ANU